Pressure sensors find wide use in industry: U.S. Pat. Nos. 6,452,427, 6,445,053, 6,229,190, 6,167,763, 6,112,598, 5,808,210, 5,747,705, 5,585,311, 5,535,135, 5,528,452, 5,459,351, 5,453,628, 5,155,061 4,098,133, 4,008,619.
The topside of a typical pressure sensor includes implanted piezoresistors to convert the pressure to an electrical signal, contacts to metal interconnections and bond pads used for wire bonding.
Silicon piezoresistor low pressure transducers can not be made cost effectively with a full scale output large enough to interface to control electronics. The size of the diaphragm and therefore the size of the die required to produce a sufficient span make the die cost prohibitive. This invention solves the problem by amplifying the signal of the transducer and allows the diaphragm/die size to remain small enough to be cost effective and provides sufficient span to the control electronics.
For low level pressure sensor, the sensitivity of the diaphragm is proportion to the size and thickness of the diaphragm. Larger signals require larger diaphragms, which are not cost effective. Therefore, for low pressure sensors, a method is needed to be able to interface the sensor with an ASIC that will do signal conditioning and temperature compensation for the sensor.